Patent GB-676622-A (GB)
Title: Calculating electron discharge device
IPC: H03K29/00
Filed: 1948-02-27
Abstract: 676,622. Cathode-ray tubes. RADIO CORPORATION OF AMERICA. Feb. 27, 1948 [July 30, 1943], No. 6129/48. Class 39 (i). [Also in Group XIX] An electron discharge calculating device. comprises means for generating an electron beam, secondary emissive target areas spaced along the direction of projection of the beam, means for defleeting the beam from one to another of the target areas, and a plurality of secondary electron collectors at different potentials to collect secondary electrons from the different target areas respectively. In one form, Figs. 6, 7 the electron gun, deflecting electrodes and target structures are arranged in seven layers 15 ... 21, each layer comprising two groups of fourteen electrode units each. Consecutive layers are separated by groups of three mica sheets B, D, F, which serve to mount and insulate the various electrodes. 196 electron beams are formed by cathode 11, two coaxial slotted cylinders 23, 24 serving as first anode and suppressor, respectively and the electrodes 7 which are also part of the deflecting system. Electrodes 23, 24 may be made by punching seamless tubing or by bending two flat punched sheets into semi-cylinders and welding them along long flanges 25, 26. They have tabs (not shown) for mounting them from the micas. The deflection system comprises three electrodes 6, 7, and 77, Fig. 9, at fixed potentials and four electrodes 1, 2, 3, 4 whose potentials can assume one of two values. Input signals representing digits of numbers to be added or multiplied are applied to electrodes 1, 2 and the targets 8, 9 of each unit are connected to deflecting plates 3, 4 of other units by a suitable system of connections indicated in Fig. 5 (not shown), and Fig. 6. Electrodes 1 are connected in vertical columns, and electrodes 2 are connected in layers by semi-circular rings 30, Figs. 6, 8. The plates 3, 4, targets, and connections between them are formed from single metal blanks as shown in Fig. 8, and are formed of a material of high secondary emissivity, e.g. a Mg-Ag alloy. The collectors 31, 32, Figs. 6, 9, are made up of punched laminµ-fifteen to each layer-the oval holes in which surround the indicator and carry-over targets 8, 9. They are carried on supporting rods 33, Fig. 6; the central lamina of each set of fifteen has no oval openings and serves as a shield between targets 8, 9. The device requires 60-70 external leads which cannot readily be sealed through a glass envelope. Consequently a steel envelope 3, Fig. 11, with end cups 35, 36 is used, the cup 35 carrying the exhaust tube 37 and the cup 36 the electrode leads. In manufacture, metallic eyelets are copper brazed to the holes in the cup 36, the wires are held in the holes and glass sleeves are slipped over the eyelets and the seals made. Pins 101, 103 also copper brazed to holes in the cup 36 and of different diameters, serve as locating means to align the base correctly with the socket. The lead wires are plugged directly into a socket having 64 contacts which are free to move a little radially and tangentially and to rotate slightly so as to compensate for variations in alignment of the press wires without straining the glass seals. Contact springs are provided. Electrodes 7 are always positive with respect to electrodes 1 so that the beam is always deflected towards electrodes 7; it is stated that consequently any material evaporated from the cathode which travels in straight lines cannot reach the targets, and also electrodes 7 collect stray electrons. The collectors 31, 32 may be at different potentials. It is shown that the targets will always assume one or the other of the two collector potentials but not an intermediate potential even when the beam is divided between the two parts of the targets. The arrangement is used as a calculating device and works on the binary system. A single electrode system-one of the many used in Fig. 6- is shown diagrammatically in Figs. 3 and 4. For multiplication, two digits to be multiplied are applied to plates 1, 2, respectively, and the " indicator " and " carryover " signals from other targets are applied to plates 3, 4. The electrode arrangement is such that the beam passes on one or the other side of the " island " electrode 6 according to the potential of electrode 1 but strikes the target in the same place whichever path it takes. If the beam follows the left-hand path it is unaffected by the potential of electrode 2 owing to the shielding effect of 6 but if it follows the right-hand path the electrodes 1 and 2 produce additive deflections. Further additive deflections are produced by 3, 4, the polarity of 4 being reversed as it is on the opposite side of the beam. The indicator and carry-over signals generated by the system are taken from targets 8, 9, respectively. Arrangements are described whereby a further number may be added to the product of two numbers, e.g. by using a supplementary layer of electrode systems. Some of the electrodes in one layer may be covered with fluorescent material to give a visual indication of the final result, which can be observed through translucent windows in the dome protecting the exhaust tube. Two computers may be directly coupled to one another. The Specification as open to inspection under Sect. 91, refers to the use of jigs in making the terminal construction of Fig. 11. This subjectmatter does not appear in the Specification as accepted.